#![forbid(unsafe_code)]

use std::sync::Arc;
use std::sync::Mutex;
use std::collections::HashMap;
use thiserror::Error;

// 导入安全FFI模块
use crate::{FFIError, FFIResult, SafeMemoryBuffer};

// 从exokernel导入的类型
type CapabilityId = u64;
type PhysicalAddress = u64;
type VirtualAddress = u64;

// 资源类型枚举
#[repr(C)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ResourceType {
    Memory = 1,
    Cpu = 2,
    Io = 3,
    Interrupt = 4,
}

// 内存权限结构体
#[repr(C)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub struct MemoryPermissions {
    pub read: bool,
    pub write: bool,
    pub execute: bool,
    _reserved: u16, // 修复u61类型错误，改为u16
}

impl Default for MemoryPermissions {
    fn default() -> Self {
        MemoryPermissions {
            read: false,
            write: false,
            execute: false,
            _reserved: 0,
        }
    }
}

impl MemoryPermissions {
    // 创建具有读取权限的内存权限
    pub fn read_only() -> Self {
        MemoryPermissions {
            read: true,
            write: false,
            execute: false,
            _reserved: 0,
        }
    }
    
    // 创建具有读写权限的内存权限
    pub fn read_write() -> Self {
        MemoryPermissions {
            read: true,
            write: true,
            execute: false,
            _reserved: 0,
        }
    }
    
    // 创建具有执行权限的内存权限
    pub fn read_execute() -> Self {
        MemoryPermissions {
            read: true,
            write: false,
            execute: true,
            _reserved: 0,
        }
    }
    
    // 创建具有全部权限的内存权限
    pub fn read_write_execute() -> Self {
        MemoryPermissions {
            read: true,
            write: true,
            execute: true,
            _reserved: 0,
        }
    }
}

// 定义错误类型
#[derive(Error, Debug)]
pub enum ExokernelError {
    #[error("Capability not acquired")]
    CapabilityNotAcquired,
    
    #[error("Memory allocation failed")]
    MemoryAllocationFailed,
    
    #[error("Memory free failed")]
    MemoryFreeFailed,
    
    #[error("Memory mapping failed")]
    MemoryMappingFailed,
    
    #[error("Memory unmapping failed")]
    MemoryUnmappingFailed,
    
    #[error("Interrupt handler setup failed")]
    InterruptHandlerSetupFailed,
    
    #[error("CPU time slice allocation failed")]
    CpuTimeSliceFailed,
    
    #[error("IO operation failed")]
    IoOperationFailed,
    
    #[error("FFI error: {0}")]
    FFIError(#[from] FFIError),
}

// 定义结果类型
type ExokernelResult<T> = Result<T, ExokernelError>;

// 能力包装器（安全地管理exokernel能力）
pub struct Capability {
    id: CapabilityId,
    acquired: bool,
    resource_type: ResourceType,
}

impl Capability {
    // 创建新的能力包装器
    pub fn new(id: CapabilityId, resource_type: ResourceType) -> Self {
        Capability {
            id,
            acquired: false,
            resource_type,
        }
    }

    // 获取能力
    pub fn acquire(&mut self) -> ExokernelResult<bool> {
        if !self.acquired {
            // 模拟能力获取成功
            self.acquired = true;
            Ok(true)
        } else {
            Ok(true)
        }
    }

    // 释放能力
    pub fn release(&mut self) {
        if self.acquired {
            self.acquired = false;
        }
    }

    // 获取能力ID
    pub fn id(&self) -> CapabilityId {
        self.id
    }

    // 检查是否已获取
    pub fn is_acquired(&self) -> bool {
        self.acquired
    }
    
    // 获取资源类型
    pub fn resource_type(&self) -> ResourceType {
        self.resource_type
    }
}

impl Drop for Capability {
    fn drop(&mut self) {
        self.release();
    }
}

// 安全的物理内存块包装器
pub struct PhysicalMemoryBlock {
    capability: Arc<Mutex<Capability>>,
    address: PhysicalAddress,
    size: u64,
    alignment: u64,
}

impl PhysicalMemoryBlock {
    // 分配物理内存
    pub fn allocate(capability: Arc<Mutex<Capability>>, size: u64, alignment: u64) -> ExokernelResult<Self> {
        if capability.lock().map_err(|_| ExokernelError::CapabilityNotAcquired)?.resource_type != ResourceType::Memory {
            return Err(ExokernelError::CapabilityNotAcquired);
        }
        
        if size == 0 {
            return Err(ExokernelError::MemoryAllocationFailed);
        }
        
        // 模拟物理内存分配
        let address = 0x10000000; // 模拟地址
        
        Ok(PhysicalMemoryBlock {
            capability,
            address,
            size,
            alignment,
        })
    }
    
    // 获取物理地址
    pub fn address(&self) -> PhysicalAddress {
        self.address
    }
    
    // 获取大小
    pub fn size(&self) -> u64 {
        self.size
    }
    
    // 获取对齐方式
    pub fn alignment(&self) -> u64 {
        self.alignment
    }
    
    // 映射物理内存到虚拟地址空间
    pub fn map(&self, virt_addr: VirtualAddress, _perms: MemoryPermissions) -> ExokernelResult<bool> {
        if let Err(_) = self.capability.lock() {
            return Err(ExokernelError::CapabilityNotAcquired);
        }
        
        // 模拟映射成功
        Ok(true)
    }
}

impl Drop for PhysicalMemoryBlock {
    fn drop(&mut self) {
        // 模拟释放物理内存
    }
}

// 安全的内存映射包装器
pub struct MemoryMapping {
    capability: Arc<Mutex<Capability>>,
    virt_addr: VirtualAddress,
    phys_addr: PhysicalAddress,
    size: u64,
    perms: MemoryPermissions,
}

impl MemoryMapping {
    // 创建内存映射
    pub fn new(
        capability: Arc<Mutex<Capability>>,
        virt_addr: VirtualAddress,
        phys_addr: PhysicalAddress,
        size: u64,
        perms: MemoryPermissions
    ) -> ExokernelResult<Self> {
        if capability.lock().map_err(|_| ExokernelError::CapabilityNotAcquired)?.resource_type != ResourceType::Memory {
            return Err(ExokernelError::CapabilityNotAcquired);
        }
        
        // 模拟映射成功
        Ok(MemoryMapping {
            capability,
            virt_addr,
            phys_addr,
            size,
            perms,
        })
    }
    
    // 获取虚拟地址
    pub fn virt_addr(&self) -> VirtualAddress {
        self.virt_addr
    }
    
    // 获取物理地址
    pub fn phys_addr(&self) -> PhysicalAddress {
        self.phys_addr
    }
    
    // 获取大小
    pub fn size(&self) -> u64 {
        self.size
    }
    
    // 获取权限
    pub fn permissions(&self) -> MemoryPermissions {
        self.perms
    }
    
    // 安全地访问映射的内存
    pub fn access_memory(&self) -> ExokernelResult<SafeMemoryBuffer> {
        // 模拟创建一个安全的内存缓冲区
        SafeMemoryBuffer::new(self.size as usize)
            .map_err(ExokernelError::FFIError)
    }
}

impl Drop for MemoryMapping {
    fn drop(&mut self) {
        // 模拟解除映射
    }
}

// 能力管理器
pub struct CapabilityManager {
    capabilities: HashMap<String, Arc<Mutex<Capability>>>,
}

impl CapabilityManager {
    // 创建新的能力管理器
    pub fn new() -> Self {
        CapabilityManager {
            capabilities: HashMap::new(),
        }
    }
    
    // 添加能力
    pub fn add_capability(&mut self, name: &str, capability: Arc<Mutex<Capability>>) {
        self.capabilities.insert(name.to_string(), capability);
    }
    
    // 获取能力
    pub fn get_capability(&self, name: &str) -> Option<Arc<Mutex<Capability>>> {
        self.capabilities.get(name).map(Arc::clone)
    }
    
    // 移除能力
    pub fn remove_capability(&mut self, name: &str) {
        self.capabilities.remove(name);
    }
    
    // 列出所有能力
    pub fn list_capabilities(&self) -> Vec<String> {
        self.capabilities.keys().cloned().collect()
    }
    
    // 获取初始能力
    pub fn get_initial_capabilities(&mut self) -> ExokernelResult<(Arc<Mutex<Capability>>, Arc<Mutex<Capability>>)> {
        // 模拟获取初始能力
        let mem_cap_id: CapabilityId = 1;
        let cpu_cap_id: CapabilityId = 2;

        let mut mem_cap = Capability::new(mem_cap_id, ResourceType::Memory);
        let mut cpu_cap = Capability::new(cpu_cap_id, ResourceType::Cpu);

        // 尝试获取能力
        if !mem_cap.acquire()? || !cpu_cap.acquire()? {
            return Err(ExokernelError::CapabilityNotAcquired);
        }

        // 创建Arc<Mutex<Capability>>
        let mem_cap_arc = Arc::new(Mutex::new(mem_cap));
        let cpu_cap_arc = Arc::new(Mutex::new(cpu_cap));
        
        // 添加到管理器
        self.add_capability("memory", mem_cap_arc.clone());
        self.add_capability("cpu", cpu_cap_arc.clone());

        Ok((mem_cap_arc, cpu_cap_arc))
    }
}

// 最后更新：2024-01-15